1. Field of the Invention
The present invention relates to a conversion processing technique of color image signals applied to an image formation apparatus that forms an image on a recording medium by the use of a color material. In particular, the present invention relates to a creation method of a total color material amount restriction table used to convert a signal value in order to restrict the color material amount assigned to a recording medium, a program, and a recording medium suitable for the creation.
2. Description of the Related Art
An image formation apparatus such as an ink jet printer and electrophotographic picture creation apparatus forms a desired image on a recording medium by providing a color material (i.e., recording liquid) such as an ink and toner on a recording medium such as paper. At the time of image formation, when the color material is provided to the recording medium in a superimposed manner, there is a case where the recording medium may not sufficiently absorb a color material which is excessively provided. In this case, the patch color reproducibility may be impaired, the decrease in the membrane property due to an excessive color material may be caused, or a paper may be warped due to the excessive color material and a problem may be caused at the time of medium conveyance. Moreover, there is a demand to reduce the used color material amount from the viewpoint of the cost reduction.
Japanese Patent Application Laid-Open No. 2005-101934 discloses a technique of restricting the ink amount by under-color removal processing that replaces a predetermined amount of CMY signals with a K signal for the purpose of improving the reproducibility of an output image while restricting the amount of toner or ink attached per unit area from the viewpoint to prevent the excess provision of color materials (paragraph [0005] in Japanese Patent Application Laid-Open No. 2005-101934).
That is, the invention described in Japanese Patent Application Laid-Open No. 2005-101934 suggests “an image processing apparatus that supplies an image signal to an image formation apparatus that forms an image on a recording medium by a recording liquid, including: a holding unit that holds a restriction value for a total sum of signals levels of image signals output to the image formation apparatus; an input unit that inputs CMYK signals as the image signals; a first comparison unit that compares the total sum of the signal levels of the input CMYK signals and the restriction value; an under-color that performs under-color removal processing of replacing a predetermined amount of CMY signals with a K signal in a case where the total sum of the signal levels of the input CMYK signals exceeds the restriction value; a second comparison unit that compares a total sum of signal levels of the CMYK signals subjected to the under-color removal processing and the restriction value; and an adjustment unit that reduces CMY signals after the under-color removal processing by a same rate such that the total sum after the under-color removal processing is equal to or less than the restriction value in a case where the total sum after the under-color removal processing exceeds the restriction value” (claim 1 of Japanese Patent Application Laid-Open No. 2005-101934).